> What are most developers running?
The very latest, most unstable builds.
> What is probably the most thoroughly tested?
2.0.25 on Berkley DB 3.
I love (Debian) Linux, and for stability it beats the pants off Windows
and Mac OS. But it is fundamentally by and for hackers, not stability
freaks. A money-is-no-object stability-o-phile would run Solaris (and his
poor cousin would run BSD).